You think malls don’t have data on shopper movement? That a random kiosk owner can’t distinguish people who come from high school from the after-church crowd from the office workers from the tinfoil-wearing nerd always coming at 2am so that they can minimise social interaction? That they will have coffee ready for the morning shift, and beer for the club crowd?
“Knowing where people come from” does not imply ID’ing individual people, which is why I specifically mentioned that Mozilla technology. The legitimate interest is in aggregate data, and yes “lots of people come here from the brothel” is legitimate data. “This particular person did” is not: If you wear a suit and happen to come with the office crowd doesn’t mean you’re an office worker, you could be a travelling salesman.